Abstract: The effects of secd-soaking with 1% CaCl₂ on the structure of chloro-plast of wheat and the physiological and biochemical characteristics in photosynthesis under heat stress were investigated. The results suggested that Ca²⁺ treatment might well mitigate the damage of thylakoid membrane and hence assuage the decrease of rate of leaf photosynthesis caused by continuous high temperature. The further analyses with elcctrophoresis demonstrated that Ca²⁺ treatment increased the contents of pigments, PSⅡ reaction center, light-receiving pigment complex and P700-Chl a complex, enhanced the synthesis of Rubisco and, as a result, raised the rate of photosynthesis.

Key words: Wheat (T. aestivum), Calcium, Rate of photosynthesis, Thylakoid membrane